SMA-Locked Telescopic Actuator for Low-Wear Mechanical Locking
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Solution Overview
Problem
Existing telescopic actuators rely on frictional forces for locking and unlocking, leading to excessive wear, increased maintenance, and potential safety issues.
Innovation Solution
A lockable telescopic actuator using shape memory alloy (SMA) biasing elements to selectively extend or compress, allowing the locking mechanism to transition between locked and unlocked states without relying on friction, thereby reducing wear and improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frictional force is used for locking and unlocking, then the locking mechanism can maintain the locked state, but excessive wear occurs and maintenance requirements increase
Solution Approach 1:
The patent replaces the traditional friction-based mechanical locking system with a shape memory alloy-based locking mechanism. The SMA element undergoes phase transformation under thermal or electrical stimulation to generate locking force, eliminating the need for friction between locking segments and the piston. This substitution of mechanical friction with phase transformation-based actuation resolves the contradiction by maintaining reliable locking without excessive wear.
Solution Approach 2:
The patent utilizes parameter changes in the shape memory alloy material, specifically its phase transformation properties. By changing the temperature or electrical state of the SMA element, it transitions between austenite and martensite phases, generating different lengths and forces to achieve locking and unlocking states. This parameter-based control eliminates continuous friction while maintaining secure locking, resolving the wear-reliability contradiction.
2Reliability
If friction-based locking is used, then the actuator can be locked, but the system complexity increases due to additional components needed for friction engagement
Solution Approach 1:
The patent replaces complex friction-based mechanical components with a streamlined shape memory alloy-based locking mechanism. The SMA element directly engages with the piston through phase transformation-driven motion, eliminating the need for separate friction plates, springs, and adjustment mechanisms. This substitution reduces the number of moving parts while maintaining reliable locking capability.
Solution Approach 2:
The patent employs shape memory alloy as a composite material that combines structural and actuation functions. The SMA element serves both as the locking component and the actuator, integrating multiple functions into a single material system. This reduces overall device complexity by eliminating the need for separate friction-based locking components and their associated moving parts.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The SMA-based actuator reduces wear on components, requires fewer moving parts, and enhances reliability with improved redundancy, making it suitable for aerospace applications.
Implementation Method 1
a first shape memory alloy, SMA, biasing element configured to be selectively extended or compressed
Data Source
AI summary
A lockable telescopic actuator arranged to be in a locked state or in an unlocked state, the lockable telescopic actuator including: a body defining a cylindrical cavity; a piston mounted to slide in the cylindrical cavity; and a locking mechanism including a first locking segment arranged to move from a locked position to an unlocked position. In the locked position the first locking segment is engaged with the piston to prevent the piston from moving. In the unlocked position the first locking segment is disengaged from the piston to allow the piston to move. A first shape memory alloy, SMA, biasing element configured to be extended or compressed such that when the first SMA biasing element is compressed the first locking element is biased into the locked position and when the first SMA bias element is extended the first locking element is biased into the unlocked position.